System and method for remote ecg data streaming in real-time

ABSTRACT

A system and method for remote ECG data streaming in real-time is provided. A continuous connection is established between a cloud-based server and a physiological monitor. The physiological monitor includes at least two electrodes and is affixed to a chest of a patient or implanted within the patient. ECG data is collected via one or more of the electrodes and encrypted via a wireless interface on the physiological monitor using a secret key stored on the physiological monitor. The encrypted ECG data is transmitted from the cloud-based server and received on a computing device in real-time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application is a continuation of U.S. patentapplication Ser. No. 16/926,381, filed Jul. 10, 2020, pending, whichclaims priority under 35 U.S.C. § 119(e) to U.S. Provisional PatentApplication, Ser. No. 62/873,754, filed Jul. 12, 2019, U.S. ProvisionalPatent Application, Ser. No. 62/874,086, filed Jul. 15, 2019, U.S.Provisional Patent Application, Ser. No. 62/873,740, filed Jul. 12,2019, U.S. Provisional Patent Application, Ser. No. 62/962,773, filedJan. 17, 2020, and further claims priority to U.S. patent applicationSer. No. 16/919,626, filed on Jul. 2, 2020, pending, which claimspriority under 35 U.S.C. § 119(e) to U.S. Provisional PatentApplication, Ser. No. 62/870,506, filed Jul. 3, 2019, the disclosures ofwhich are incorporated by reference.

FIELD

This application relates in general to cardiac monitoring and, inparticular, to a system and method for remote ECG data streaming inreal-time.

BACKGROUND

The heart emits electrical signals as a by-product of the propagation ofthe action potentials that trigger depolarization of heart fibers. Anelectrocardiogram (ECG) measures and records such electrical potentialsto visually depict the electrical activity of the heart over time.Conventionally, dermal ECG electrodes positioned on and insertablecardiac monitors (ICMs) implanted in a patient are utilized to sensecardiac electrical activity. The sensed cardiac electrical activity isrepresented by PQRSTU waveforms that can be interpreted post-ECGrecordation to derive heart rate and physiology. The P-wave representsatrial electrical activity. The QRSTU components represent ventricularelectrical activity.

An ECG is a tool used by physicians to diagnose heart problems and otherpotential health concerns. An ECG is a snapshot of heart function,typically recorded over 12 seconds, that can help diagnose rate andregularity of heartbeats, effect of drugs or cardiac devices, includingpacemakers and implantable cardioverter-defibrillators (ICDs), andwhether a patient has heart disease. ECGs are used in-clinic duringappointments, and, as a result, are limited to recording only thoseheart-related aspects present at the time of recording. Sporadicconditions that may not show up during a spot ECG recording requireother means to diagnose them. These disorders include fainting orsyncope; rhythm disorders, such as tachyarrhythmias andbradyarrhythmias; apneic episodes; and other cardiac and relateddisorders. Thus, an ECG only provides a partial picture and can beinsufficient for complete patient diagnosis of many cardiac disorders.Long term monitoring of a patient via a dermal cardiac device or ICM canprovide a larger picture of a patient's cardiac activity, such as over atime span of 7 days or more, which can be helpful to identify conditionsand disorders that are not generally viewed during a spot ECG recording.However, the data recorded by the dermal cardiac device or ICM isgenerally accessed by a medical professional after a scheduled datatransmission which can be hours or days later.

Typically, data is downloaded from the device at preset intervals. Todownload the data, a wand or other device is placed over the patient'scardiac device to access the stored data, such as via a wirelessconnection. The accessed data can then be stored and processed. However,since the cardiac data is collected at a predetermined time such data isgenerally not useful to identify or diagnose a condition or disorder ofthe patient, unless the patient is in the office or medical facility.

Remote real-time views of the cardiac data can be useful in treating apatient, such as when a patient experiences a cardiac event. Forexample, after a patient experiences a cardiac event, such aspalpitations, the patient can contact his physician or an alert can bedelivered to the physician that a cardiac event has occurred. Thephysician can then review the patient's cardiac activity in real-time todetermine whether the patient needs additional care or should go to thehospital.

While some conventional cardiac monitors, both dermal and ICMs, includewireless data transmission, such devices do not allow for real-timestreaming of cardiac data from the device to a remote computer. Asdescribed above, the cardiac data collected by the cardiac monitor isgenerally retrieved via a wand on a tablet or other computer. Each timethe computer communicates with the server.

Therefore, a need remains for remote real-time streaming of cardiacdata.

SUMMARY

Physiological monitoring can be provided through a wearable monitor thatincludes two components, a flexible extended wear electrode patch and aremovable reusable monitor recorder. The wearable monitor sits centrally(in the midline) on the patient's chest along the sternum orientedtop-to-bottom. The placement of the wearable monitor in a location atthe sternal midline (or immediately to either side of the sternum), withits unique narrow “hourglass”-like shape, benefits long-term extendedwear by removing the requirement that ECG electrodes be continuallyplaced in the same spots on the skin throughout the monitoring period.Instead, the patient is free to place an electrode patch anywhere withinthe general region of the sternum. In addition, power is providedthrough a battery provided on the electrode patch, which avoids havingto either periodically open the housing of the monitor recorder for thebattery replacement, which also creates the potential for moistureintrusion and human error, or to recharge the battery, which canpotentially take the monitor recorder off line for hours at a time. Inaddition, the electrode patch is intended to be disposable, while themonitor recorder is a reusable component. Thus, each time that theelectrode patch is replaced, a fresh battery is provided for the use ofthe monitor recorder.

Further, long-term electrocardiographic and physiological monitoringover a period lasting up to several years in duration can be providedthrough a continuously-recording subcutaneous insertable cardiac monitor(ICM), such as one described in commonly-owned U.S. patent applicationSer. No. 15/832,385, filed Dec. 5, 2017, pending, the disclosure ofwhich is incorporated by reference. The sensing circuitry and thephysical layout of the electrodes are specifically optimized to captureelectrical signals from the propagation of low amplitude, relatively lowfrequency content cardiac action potentials, particularly the P-wavesthat are generated during atrial activation. In general, the ICM isintended to be implanted centrally and positioned axially and slightlyto either the left or right of the sternal midline in the parasternalregion of the chest. In one embodiment, an insertable cardiac monitor(ICM) for use in performing long term electrocardiographic (ECG)monitoring is provided. The monitor includes; an implantable housingincluded of a biocompatible material that is suitable for implantationwithin a living body; at least one pair of ECG sensing electrodesprovided on a ventral surface and on opposite ends of the implantablehousing operatively placed to facilitate sensing in closest proximity tothe low amplitude, low frequency content cardiac action potentials thatare generated during atrial activation; and electronic circuitryprovided within the housing assembly. The electronic circuitry includesan ECG front end circuit interfaced to a low-power microcontroller andconfigured to capture the cardiac action potentials sensed by the pairof ECG sensing electrodes which are output as ECG signals; the low powermicrocontroller operable to execute under modular micro program controlas specified in firmware, the microcontroller operable to read samplesof the ECG signals, buffer the samples of the ECG signals, compress thebuffered samples of the ECG signals, buffer the compressed samples ofthe ECG signals, and write the buffered samples into a non-volatileflash memory; and the non-volatile memory electrically interfaced withthe microcontroller and operable to store the written samples of the ECGsignals.

Remote real-time streaming of ECG and other physiological data can occurbased on a continuous communication connection between a cardiac monitorand a cloud server or between a home station and the cloud server. Thecardiac monitor encrypts and transmits the data either directly to thecloud server or via a puck to the home station. Once received by thehome station, the encrypted data is then transmitted to the cloudserver, which then transmits the data to a remote physician via acomputing device. Due to the continuous connection, the data transfer isin real-time, while the encryption provides a secure communication ofthe data.

An embodiment provides a system and method for remote ECG data streamingin real-time. A continuous connection is established between acloud-based server and a physiological monitor. The physiologicalmonitor includes at least two electrodes and is affixed to a chest of apatient or implanted within the patient. ECG data is collected via oneor more of the electrodes and encrypted via a wireless interface on thephysiological monitor using a secret key stored on the physiologicalmonitor. The encrypted ECG data is transmitted from the cloud-basedserver and received on a computing device in real-time.

Still other embodiments will become readily apparent to those skilled inthe art from the following detailed description, wherein are describedembodiments by way of illustrating the best mode contemplated. As willbe realized, other and different embodiments are possible and theembodiments' several details are capable of modifications in variousobvious respects, all without departing from their spirit and the scope.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are diagrams showing, by way of examples, an extended wearelectrocardiography and physiological sensor monitor, including amonitor recorder in accordance with one embodiment, respectively fittedto the sternal region of a female patient and a male patient.

FIG. 3 is a perspective view showing an extended wear electrode patchwith a monitor recorder in accordance with one embodiment inserted.

FIG. 4 is a perspective view showing the monitor recorder of FIG. 3.

FIG. 5 is a perspective view showing the extended wear electrode patchof FIG. 3 without a monitor recorder inserted.

FIG. 6 is a bottom plan view of the monitor recorder of FIG. 3.

FIG. 7 is a top view showing the flexible circuit of the extended wearelectrode patch of FIG. 3 when mounted above the flexible backing.

FIG. 8 is a functional block diagram showing the component architectureof the circuitry of the monitor recorder of FIG. 3.

FIG. 9 is a functional block diagram showing the circuitry of theextended wear electrode patch of FIG. 3.

FIG. 10 is a flow diagram showing a monitor recorder-implemented methodfor monitoring ECG data for use in the monitor recorder of FIG. 3.

FIG. 11 is a graph showing, by way of example, a typical ECG waveform.

FIG. 12 is a diagram showing, by way of example, a subcutaneous P-wavecentric insertable cardiac monitor (ICM) for long termelectrocardiographic monitoring in accordance with one embodiment.

FIGS. 13 and 14 are respectively top and bottom perspective viewsshowing the ICM of FIG. 12.

FIG. 15 is a bottom perspective view showing the ICM of FIG. 12 inaccordance with a further embodiment.

FIGS. 16 and 17 are respectively top and bottom perspective viewsshowing an ICM in accordance with a still further embodiment.

FIG. 18 is a functional block diagram showing the P-wave focusedcomponent architecture of the circuitry of the ICM of FIG. 12.

FIG. 19 is a functional block diagram showing a system for wirelesslyinterfacing with an ICM in accordance with one embodiment.

FIG. 20 is a functional block diagram showing a system 300 for obtainingECG data from a cardiac monitor, in accordance with one embodiment.

FIG. 21 is a functional block diagram showing a system 320 for real-timeremote streaming of ECG data, in accordance with one embodiment.

DETAILED DESCRIPTION Related Applications

This non-provisional patent application is related to commonly-assignedU.S. Pat. No. 9,545,204, issued Jan. 17, 2017 to Bishay et al.; U.S.Pat. No. 9,730,593, issued Aug. 15, 2017 to Felix et al.; U.S. Pat. No.9,717,432, issued Aug. 1, 2017 to Felix et al.; U.S. Pat. No. 9,775,536,issued Oct. 3, 2017 to Felix et al.; U.S. Pat. No. 9,433,380, issuedSep. 6, 2016 to Bishay et al.; U.S. Pat. No. 9,655,538, issued May 23,2017 to Felix et al.; U.S. Pat. No. 9,364,155, issued Jun. 14, 2016 toBardy et al.; U.S. Pat. No. 9,737,224, issued Aug. 22, 2017 to Bardy etal.; U.S. Pat. No. 9,433,367, issued Sep. 6, 2016 to Felix et al.; U.S.Pat. No. 9,700,227, issued Jul. 11, 2017 to Bishay et al.; U.S. Pat. No.9,717,433, issued Aug. 1, 2017 to Felix et al.; U.S. Pat. No. 9,615,763,issued Apr. 11, 2017 to Felix et al.; U.S. Pat. No. 9,642,537, issuedMay 9, 2017 to Felix et al.; U.S. Pat. No. 9,408,545, issued Aug. 9,2016 to Felix et al.; U.S. Pat. No. 9,655,537, issued May 23, 2017 toBardy et al.; U.S. Pat. No. 10,165,946, issued Jan. 1, 2019 to Bardy etal.; U.S. Pat. No. 10,433,748, issued Oct. 8, 2019 to Bishay et al.;U.S. Pat. No. 10,667,711, issued Jun. 2, 2020; U.S. Pat. No. 9,619,660,issued Apr. 11, 2017 to Felix et al.; U.S. Pat. No. 10,463,269, issuedNov. 5, 2019 to Boleyn et al.; U.S. Pat. No. 9,408,551, issued Aug. 9,2016 to Bardy et al.; U.S. Pat. No. 10,736,531, issued Aug. 11, 2020 toBardy et al.; U.S. Pat. No. 10,736,529, issued Aug. 11, 2020 to Bardy etal.; U.S. Patent Application Publication No. 2019/0117099, publishedApr. 25, 2019 to Bardy et al.; U.S. Patent Application Publication No.2019/0099105, published Apr. 4, 2019 to Felix et al.; U.S. Pat. No.10,624,551, issued Apr. 21, 2020, to Bardy et al.; U.S. Pat. No.10,251,576, issued Apr. 9, 2019 to Bardy et al.; U.S. Pat. No.9,345,414, issued May 24, 2016 to Bardy et al.; U.S. Pat. No.10,433,751, issued Oct. 8, 2019 to Bardy et al.; U.S. Pat. No.9,504,423, issued Nov. 29, 2016 to Bardy et al.; U.S. Patent ApplicationPublication No. 2019/0167139, published Jun. 6, 2019 to Bardy et al.;U.S. Design Patent No. D717955, issued Nov. 18, 2014 to Bishay et al.;U.S. Design Patent No. D744659, issued Dec. 1, 2015 to Bishay et al.;U.S. Design Patent No. D838370, issued Jan. 15, 2019 to Bardy et al.;U.S. Design Patent No. D801528, issued Oct. 31, 2017 to Bardy et al.;U.S. Design Patent No. D766447, issued Sep. 13, 2016 to Bishay et al.;U.S. Design Patent No. D793566, issued Aug. 1, 2017 to Bishay et al.;U.S. Design Patent No. D831833, issued Oct. 23, 2018 to Bishay et al.;U.S. Design Patent No. D892340, issued Aug. 4, 2020 to Bishay et al, andProvisional Patent Application No. 62/870,506, entitled: “SubcutaneousP-Wave Centric Cardiac Monitor With Energy Harvesting Capabilities,”filed Jul. 3, 2019, expired, the disclosures of which are incorporatedby reference.

Overview

Physiological monitoring can be provided through a wearable monitor thatincludes two components, a flexible extended wear electrode patch and aremovable reusable monitor recorder. FIGS. 1 and 2 are diagrams showing,by way of examples, an extended wear electrocardiography andphysiological sensor monitor 12, including a monitor recorder 14 inaccordance with one embodiment, respectively fitted to the sternalregion of a female patient 10 and a male patient 11. The wearablemonitor 12 sits centrally (in the midline) on the patient's chest alongthe sternum 13 oriented top-to-bottom with the monitor recorder 14preferably situated towards the patient's head. In a further embodiment,the orientation of the wearable monitor 12 can be correctedpost-monitoring, as further described infra. The electrode patch 15 isshaped to fit comfortably and conformal to the contours of the patient'schest approximately centered on the sternal midline 16 (or immediatelyto either side of the sternum 13). The distal end of the electrode patch15 extends towards the Xiphoid process and, depending upon the patient'sbuild, may straddle the region over the Xiphoid process. The proximalend of the electrode patch 15, located under the monitor recorder 14, isbelow the manubrium and, depending upon patient's build, may straddlethe region over the manubrium.

The placement of the wearable monitor 12 in a location at the sternalmidline 16 (or immediately to either side of the sternum 13)significantly improves the ability of the wearable monitor 12 tocutaneously sense cardiac electric signals, particularly the P-wave (oratrial activity) and, to a lesser extent, the QRS interval signals inthe ECG waveforms that indicate ventricular activity. The sternum 13overlies the right atrium of the heart and the placement of the wearablemonitor 12 in the region of the sternal midline 13 puts the ECGelectrodes of the electrode patch 15 in a location better adapted tosensing and recording P-wave signals than other placement locations,say, the upper left pectoral region. In addition, placing the lower orinferior pole (ECG electrode) of the electrode patch 15 over (or near)the Xiphoid process facilitates sensing of right ventricular activityand provides superior recordation of the QRS interval.

During use, the electrode patch 15 is first adhesed to the skin alongthe sternal midline 16 (or immediately to either side of the sternum13). A monitor recorder 14 is then snapped into place on the electrodepatch 15 to initiate ECG monitoring. FIG. 3 is a perspective viewshowing an extended wear electrode patch 15 with a monitor recorder 14in accordance with one embodiment inserted. The body of the electrodepatch 15 is preferably constructed using a flexible backing 20 formed asan elongated strip 21 of wrap knit or similar stretchable material witha narrow longitudinal mid-section 23 evenly tapering inward from bothsides. A pair of cut-outs 22 between the distal and proximal ends of theelectrode patch 15 create a narrow longitudinal midsection 23 or“isthmus” and defines an elongated “hourglass”-like shape, when viewedfrom above.

The electrode patch 15 incorporates features that significantly improvewearability, performance, and patient comfort throughout an extendedmonitoring period. During wear, the electrode patch 15 is susceptible topushing, pulling, and torqueing movements, including compressional andtorsional forces when the patient bends forward, and tensile andtorsional forces when the patient leans backwards. To counter thesestress forces, the electrode patch 15 incorporates strain and crimpreliefs, such as described in commonly-assigned U.S. Patent, entitled“Extended Wear Electrocardiography Patch,” U.S. Pat. No. 9,545,204,issued on Jan. 17, 2017, the disclosure of which is incorporated byreference. In addition, the cut-outs 22 and longitudinal midsection 23help minimize interference with and discomfort to breast tissue,particularly in women (and gynecomastic men). The cut-outs 22 andlongitudinal midsection 23 further allow better conformity of theelectrode patch 15 to sternal bowing and to the narrow isthmus of flatskin that can occur along the bottom of the intermammary cleft betweenthe breasts, especially in buxom women. The cut-outs 22 and longitudinalmidsection 23 help the electrode patch 15 fit nicely between a pair offemale breasts in the intermammary cleft. Still other shapes, cut-outsand conformities to the electrode patch 15 are possible.

The monitor recorder 14 removably and reusably snaps into anelectrically non-conductive receptacle 25 during use. The monitorrecorder 14 contains electronic circuitry for recording and storing thepatient's electrocardiography as sensed via a pair of ECG electrodesprovided on the electrode patch 15, as further described infra beginningwith reference to FIG. 8. The non-conductive receptacle 25 is providedon the top surface of the flexible backing 20 with a retention catch 26and tension clip 27 molded into the non-conductive receptacle 25 toconformably receive and securely hold the monitor recorder 14 in place.

The monitor recorder 14 includes a sealed housing that snaps into placein the non-conductive receptacle 25. FIG. 4 is a perspective viewshowing the monitor recorder 14 of FIG. 3. The sealed housing 50 of themonitor recorder 14 intentionally has a rounded isoscelestrapezoidal-like shape 52, when viewed from above, such as described incommonly-assigned U.S. Design Patent, entitled “ElectrocardiographyMonitor,” No. D717955, issued on Nov. 18, 2014, the disclosure of whichis incorporated by reference. The edges 51 along the top and bottomsurfaces are rounded for patient comfort. The sealed housing 50 isapproximately 47 mm long, 23 mm wide at the widest point, and 7 mm high,excluding a patient-operable tactile-feedback button 55. The sealedhousing 50 can be molded out of polycarbonate, ABS, or an alloy of thosetwo materials. The button 55 is waterproof and the button's top outersurface is molded silicon rubber or similar soft pliable material. Aretention detent 53 and tension detent 54 are molded along the edges ofthe top surface of the housing 50 to respectively engage the retentioncatch 26 and the tension clip 27 molded into non-conductive receptacle25. Other shapes, features, and conformities of the sealed housing 50are possible.

The electrode patch 15 is intended to be disposable. The monitorrecorder 14, however, is reusable and can be transferred to successiveelectrode patches 15 to ensure continuity of monitoring. The placementof the wearable monitor 12 in a location at the sternal midline 16 (orimmediately to either side of the sternum 13) benefits long-termextended wear by removing the requirement that ECG electrodes becontinually placed in the same spots on the skin throughout themonitoring period. Instead, the patient is free to place an electrodepatch 15 anywhere within the general region of the sternum 13.

As a result, at any point during ECG monitoring, the patient's skin isable to recover from the wearing of an electrode patch 15, whichincreases patient comfort and satisfaction, while the monitor recorder14 ensures ECG monitoring continuity with minimal effort. A monitorrecorder 14 is merely unsnapped from a worn out electrode patch 15, theworn out electrode patch 15 is removed from the skin, a new electrodepatch 15 is adhered to the skin, possibly in a new spot immediatelyadjacent to the earlier location, and the same monitor recorder 14 issnapped into the new electrode patch 15 to reinitiate and continue theECG monitoring.

During use, the electrode patch 15 is first adhered to the skin in thesternal region. FIG. 5 is a perspective view showing the extended wearelectrode patch 15 of FIG. 3 without a monitor recorder 14 inserted. Aflexible circuit 32 is adhered to each end of the flexible backing 20. Adistal circuit trace 33 and a proximal circuit trace (not shown)electrically couple ECG electrodes (not shown) to a pair of electricalpads 34. The electrical pads 34 are provided within a moisture-resistantseal 35 formed on the bottom surface of the non-conductive receptacle25. When the monitor recorder 14 is securely received into thenon-conductive receptacle 25, that is, snapped into place, theelectrical pads 34 interface to electrical contacts (not shown)protruding from the bottom surface of the monitor recorder 14, and themoisture-resistant seal 35 enables the monitor recorder 14 to be worn atall times, even during bathing or other activities that could expose themonitor recorder 14 to moisture.

In addition, a battery compartment 36 is formed on the bottom surface ofthe non-conductive receptacle 25, and a pair of battery leads (notshown) electrically interface the battery to another pair of theelectrical pads 34. The battery contained within the battery compartment35 can be replaceable, rechargeable or disposable.

The monitor recorder 14 draws power externally from the battery providedin the non-conductive receptacle 25, thereby uniquely obviating the needfor the monitor recorder 14 to carry a dedicated power source. FIG. 6 isa bottom plan view of the monitor recorder 14 of FIG. 3. A cavity 58 isformed on the bottom surface of the sealed housing 50 to accommodate theupward projection of the battery compartment 36 from the bottom surfaceof the non-conductive receptacle 25, when the monitor recorder 14 issecured in place on the non-conductive receptacle 25. A set ofelectrical contacts 56 protrude from the bottom surface of the sealedhousing 50 and are arranged in alignment with the electrical pads 34provided on the bottom surface of the non-conductive receptacle 25 toestablish electrical connections between the electrode patch 15 and themonitor recorder 14. In addition, a seal coupling 57 circumferentiallysurrounds the set of electrical contacts 56 and securely mates with themoisture-resistant seal 35 formed on the bottom surface of thenon-conductive receptacle 25.

The placement of the flexible backing 20 on the sternal midline 16 (orimmediately to either side of the sternum 13) also helps to minimize theside-to-side movement of the wearable monitor 12 in the left- andright-handed directions during wear. To counter the dislodgment of theflexible backing 20 due to compressional and torsional forces, a layerof non-irritating adhesive, such as hydrocolloid, is provided at leastpartially on the underside, or contact, surface of the flexible backing20, but only on the distal end 30 and the proximal end 31. As a result,the underside, or contact surface of the longitudinal midsection 23 doesnot have an adhesive layer and remains free to move relative to theskin. Thus, the longitudinal midsection 23 forms a crimp relief thatrespectively facilitates compression and twisting of the flexiblebacking 20 in response to compressional and torsional forces. Otherforms of flexible backing crimp reliefs are possible.

Unlike the flexible backing 20, the flexible circuit 32 is only able tobend and cannot stretch in a planar direction. The flexible circuit 32can be provided either above or below the flexible backing 20. FIG. 7 isa top view showing the flexible circuit 32 of the extended wearelectrode patch 15 of FIG. 3 when mounted above the flexible backing 20.A distal ECG electrode 38 and proximal ECG electrode 39 are respectivelycoupled to the distal and proximal ends of the flexible circuit 32. Astrain relief 40 is defined in the flexible circuit 32 at a locationthat is partially underneath the battery compartment 36 when theflexible circuit 32 is affixed to the flexible backing 20. The strainrelief 40 is laterally extendable to counter dislodgment of the ECGelectrodes 38, 39 due to tensile and torsional forces. A pair of strainrelief cutouts 41 partially extend transversely from each opposite sideof the flexible circuit 32 and continue longitudinally towards eachother to define in ‘S’-shaped pattern, when viewed from above. Thestrain relief respectively facilitates longitudinal extension andtwisting of the flexible circuit 32 in response to tensile and torsionalforces. Other forms of circuit board strain relief are possible.

ECG monitoring and other functions performed by the monitor recorder 14are provided through a micro controlled architecture. FIG. 8 is afunctional block diagram showing the component architecture of thecircuitry 60 of the monitor recorder 14 of FIG. 3. The circuitry 60 isexternally powered through a battery provided in the non-conductivereceptacle 25 (shown in FIG. 5). Both power and raw ECG signals, whichoriginate in the pair of ECG electrodes 38, 39 (shown in FIG. 7) on thedistal and proximal ends of the electrode patch 15, are received throughan external connector 65 that mates with a corresponding physicalconnector on the electrode patch 15. The external connector 65 includesthe set of electrical contacts 56 that protrude from the bottom surfaceof the sealed housing 50 and which physically and electrically interfacewith the set of pads 34 provided on the bottom surface of thenon-conductive receptacle 25. The external connector includes electricalcontacts 56 for data download, microcontroller communications, power,analog inputs, and a peripheral expansion port. The arrangement of thepins on the electrical connector 65 of the monitor recorder 14 and thedevice into which the monitor recorder 14 is attached, whether anelectrode patch 15 or download station (not shown), follow the sameelectrical pin assignment convention to facilitate interoperability. Theexternal connector 65 also serves as a physical interface to a downloadstation that permits the retrieval of stored ECG monitoring data,communication with the monitor recorder 14, and performance of otherfunctions.

Operation of the circuitry 60 of the monitor recorder 14 is managed by amicrocontroller 61. The micro-controller 61 includes a program memoryunit containing internal flash memory that is readable and writeable.The internal flash memory can also be programmed externally. Themicro-controller 61 draws power externally from the battery provided onthe electrode patch 15 via a pair of the electrical contacts 56. Themicrocontroller 61 connects to the ECG front end circuit 63 thatmeasures raw cutaneous electrical signals and generates an analog ECGsignal representative of the electrical activity of the patient's heartover time.

The circuitry 60 of the monitor recorder 14 also includes a flash memory62, which the micro-controller 61 uses for storing ECG monitoring dataand other physiology and information. The flash memory 62 also drawspower externally from the battery provided on the electrode patch 15 viaa pair of the electrical contacts 56. Data is stored in a serial flashmemory circuit, which supports read, erase and program operations over acommunications bus. The flash memory 62 enables the microcontroller 61to store digitized ECG data. The communications bus further enables theflash memory 62 to be directly accessed externally over the externalconnector 65 when the monitor recorder 14 is interfaced to a downloadstation.

The circuitry 60 of the monitor recorder 14 further includes anactigraphy sensor 64 implemented as a 3-axis accelerometer. Theaccelerometer may be configured to generate interrupt signals to themicrocontroller 61 by independent initial wake up and free fall events,as well as by device position. In addition, the actigraphy provided bythe accelerometer can be used during post-monitoring analysis to correctthe orientation of the monitor recorder 14 if, for instance, the monitorrecorder 14 has been inadvertently installed upside down, that is, withthe monitor recorder 14 oriented on the electrode patch 15 towards thepatient's feet, as well as for other event occurrence analyses.

The microcontroller 61 includes an expansion port that also utilizes thecommunications bus. External devices, separately drawing powerexternally from the battery provided on the electrode patch 15 or othersource, can interface to the microcontroller 61 over the expansion portin half duplex mode. For instance, an external physiology sensor can beprovided as part of the circuitry 60 of the monitor recorder 14, or canbe provided on the electrode patch 15 with communication with themicro-controller 61 provided over one of the electrical contacts 56. Thephysiology sensor can include an SpO₂ sensor, blood pressure sensor,temperature sensor, respiratory rate sensor, glucose sensor, airflowsensor, volumetric pressure sensing, or other types of sensor ortelemetric input sources. In a further embodiment, a wireless interfacefor interfacing with other wearable (or implantable) physiologymonitors, as well as data offload and programming, can be provided aspart of the circuitry 60 of the monitor recorder 14, or can be providedon the electrode patch 15 with communication with the micro-controller61 provided over one of the electrical contacts 56.

Finally, the circuitry 60 of the monitor recorder 14 includespatient-interfaceable components, including a tactile feedback button66, which a patient can press to mark events or to perform otherfunctions, and a buzzer 67, such as a speaker, magnetic resonator orpiezoelectric buzzer. The buzzer 67 can be used by the microcontroller61 to output feedback to a patient such as to confirm power up andinitiation of ECG monitoring. Still other components as part of thecircuitry 60 of the monitor recorder 14 are possible.

While the monitor recorder 14 operates under micro control, most of theelectrical components of the electrode patch 15 operate passively. FIG.9 is a functional block diagram showing the circuitry 70 of the extendedwear electrode patch 15 of FIG. 3. The circuitry 70 of the electrodepatch 15 is electrically coupled with the circuitry 60 of the monitorrecorder 14 through an external connector 74. The external connector 74is terminated through the set of pads 34 provided on the bottom of thenon-conductive receptacle 25, which electrically mate to correspondingelectrical contacts 56 protruding from the bottom surface of the sealedhousing 50 to electrically interface the monitor recorder 14 to theelectrode patch 15.

The circuitry 70 of the electrode patch 15 performs three primaryfunctions. First, a battery 71 is provided in a battery compartmentformed on the bottom surface of the non-conductive receptacle 25. Thebattery 71 is electrically interfaced to the circuitry 60 of the monitorrecorder 14 as a source of external power. The unique provisioning ofthe battery 71 on the electrode patch 15 provides several advantages.First, the locating of the battery 71 physically on the electrode patch15 lowers the center of gravity of the overall wearable monitor 12 andthereby helps to minimize shear forces and the effects of movements ofthe patient and clothing. Moreover, the housing 50 of the monitorrecorder 14 is sealed against moisture and providing power externallyavoids having to either periodically open the housing 50 for the batteryreplacement, which also creates the potential for moisture intrusion andhuman error, or to recharge the battery, which can potentially take themonitor recorder 14 off line for hours at a time. In addition, theelectrode patch 15 is intended to be disposable, while the monitorrecorder 14 is a reusable component. Each time that the electrode patch15 is replaced, a fresh battery is provided for the use of the monitorrecorder 14, which enhances ECG monitoring performance quality andduration of use. Finally, the architecture of the monitor recorder 14 isopen, in that other physiology sensors or components can be added byvirtue of the expansion port of the microcontroller 61. Requiring thoseadditional sensors or components to draw power from a source external tothe monitor recorder 14 keeps power considerations independent of themonitor recorder 14. Thus, a battery of higher capacity could beintroduced when needed to support the additional sensors or componentswithout effecting the monitor recorders circuitry 60.

Second, the pair of ECG electrodes 38, 39 respectively provided on thedistal and proximal ends of the flexible circuit 32 are electricallycoupled to the set of pads 34 provided on the bottom of thenon-conductive receptacle 25 by way of their respective circuit traces33, 37. The signal ECG electrode 39 includes a protection circuit 72,which is an inline resistor that protects the patient from excessiveleakage current.

Last, in a further embodiment, the circuitry 70 of the electrode patch15 includes a cryptographic circuit 73 to authenticate an electrodepatch 15 for use with a monitor recorder 14. The cryptographic circuit73 includes a device capable of secure authentication and validation.The cryptographic device 73 ensures that only genuine, non-expired,safe, and authenticated electrode patches 15 are permitted to providemonitoring data to a monitor recorder 14.

The monitor recorder 14 continuously monitors the patient's heart rateand physiology. FIG. 10 is a flow diagram showing a monitorrecorder-implemented method 100 for monitoring ECG data for use in themonitor recorder 14 of FIG. 3. Initially, upon being connected to theset of pads 34 provided with the non-conductive receptacle 25 when themonitor recorder 14 is snapped into place, the microcontroller 61executes a power up sequence (step 101). During the power up sequence,the voltage of the battery 71 is checked, the state of the flash memory62 is confirmed, both in terms of operability check and availablecapacity, and microcontroller operation is diagnostically confirmed. Ina further embodiment, an authentication procedure between themicrocontroller 61 and the electrode patch 15 are also performed.

Following satisfactory completion of the power up sequence, an iterativeprocessing loop (steps 102-109) is continually executed by themicrocontroller 61. During each iteration (step 102) of the processingloop, the ECG frontend 63 (shown in FIG. 8) continually senses thecutaneous ECG electrical signals (step 103) via the ECG electrodes 38,29 and is optimized to maintain the integrity of the P-wave. A sample ofthe ECG signal is read (step 104) by the microcontroller 61 by samplingthe analog ECG signal output front end 63. FIG. 11 is a graph showing,by way of example, a typical ECG waveform 110. The x-axis representstime in approximate units of tenths of a second. The y-axis representscutaneous electrical signal strength in approximate units of millivolts.The P-wave 111 has a smooth, normally upward, that is, positive,waveform that indicates atrial depolarization. The QRS complex usuallybegins with the downward deflection of a Q wave 112, followed by alarger upward deflection of an R-wave 113, and terminated with adownward waveform of the S wave 114, collectively representative ofventricular depolarization. The T wave 115 is normally a modest upwardwaveform, representative of ventricular depolarization, while the U wave116, often not directly observable, indicates the recovery period of thePurkinje conduction fibers.

Sampling of the R-to-R interval enables heart rate informationderivation. For instance, the R-to-R interval represents the ventricularrate and rhythm, while the P-to-P interval represents the atrial rateand rhythm. Importantly, the PR interval is indicative ofatrioventricular (AV) conduction time and abnormalities in the PRinterval can reveal underlying heart disorders, thus representinganother reason why the P-wave quality achievable by the extended wearambulatory electrocardiography and physiological sensor monitordescribed herein is medically unique and important. The long-termobservation of these ECG indicia, as provided through extended wear ofthe wearable monitor 12, provides valuable insights to the patient'scardiac function and overall well-being.

Each sampled ECG signal, in quantized and digitized form, is temporarilystaged in buffer (step 105), pending compression preparatory to storagein the flash memory 62 (step 106). Following compression, the compressedECG digitized sample is again buffered (step 107), then written to theflash memory 62 (step 108) using the communications bus. Processingcontinues (step 109), so long as the monitoring recorder 14 remainsconnected to the electrode patch 15 (and storage space remains availablein the flash memory 62), after which the processing loop is exited andexecution terminates. Still other operations and steps are possible.

In a further embodiment, physiological monitoring and data collection,such as per the method 100 described above with reference to FIG. 10,can also be implemented by a continuously-recording subcutaneousinsertable cardiac monitor (ICM), such as one described incommonly-owned U.S. patent application Ser. No. 15/832,385, filed Dec.5, 2017, pending, the disclosure of which is incorporated by reference.The ICM can be used for conducting a long-term electrocardiographic andphysiological monitoring over a period lasting up to several years induration. FIG. 12 is a diagram showing, by way of example, asubcutaneous P-wave centric ICM 212 for long term electrocardiographicmonitoring in accordance with one embodiment. The ICM 212 is implantedin the parasternal region 211 of a patient 10. The sensing circuitry andcomponents, compression algorithms, and the physical layout of theelectrodes are specifically optimized to capture electrical signals fromthe propagation of low amplitude, relatively low frequency contentcardiac action potentials, particularly the P-waves generated duringatrial activation. The position and placement of the ICM 212 coupled toengineering considerations that optimize the ICM's sensing circuitry,discussed infra, aid in demonstrating the P-wave clearly.

Implantation of a P-wave centric ICM 212 in the proper subcutaneous sitefacilitates the recording of high quality ECG data with a gooddelineation of the P-wave. In general, the ICM 212 is intended to beimplanted anteriorly and be positioned axially and slightly to eitherthe right or left of the sternal midline in the parasternal region 211of the chest, or if sufficient subcutaneous fat exists, directly overthe sternum. Optimally, the ICM 212 is implanted in a location leftparasternally to bridge the left atrial appendage. However, eitherlocation to the right or left of the sternal midline is acceptable;placement of the device, if possible, should bridge the vertical heightof the heart, which lies underneath the sternum 203, thereby placing theICM 212 in close proximity to the anterior right atrium and the leftatrial appendage that lie immediately beneath.

The ICM 212 is shaped to fit comfortably within the body under the skinand to conform to the contours of the patient's parasternal region 211when implanted immediately to either side of the sternum 203, but couldbe implanted in other locations of the body. In most adults, theproximal end 213 of the ICM 212 is generally positioned below themanubrium 8 but, depending upon patient's vertical build, the ICM 212may actually straddle the region over the manubrium 8. The distal end214 of the ICM 212 generally extends towards the xiphoid process 9 andlower sternum but, depending upon the patient's build, may actuallystraddle the region over or under the xiphoid process 9, lower sternumand upper abdomen.

Although internal tissues, body structures, and tissue boundaries canadversely affect the current strength and signal fidelity of all bodysurface potentials, subsurface low amplitude cardiac action potentials,particularly P-wave signals with a normative amplitude of less than 0.25millivolts (mV) and a normative duration of less than 120 milliseconds(ms), are most apt to be negatively impacted by these factors. Theatria, which generate the P wave, are mostly located posteriorly withinthe thoracic cavity (with the exception of the anterior right atrium,right atrial appendage and left atrial appendage). The majority of theleft atrium constitutes the portion of the heart furthest away from thesurface of the skin on the chest and harbors the atrial tissue mostlikely to be the source of serious arrhythmias, like atrialfibrillation. Conversely, the ventricles, which generate largeramplitude signals, are located anteriorly as in the case of the anteriorright ventricle and most of the anterior left ventricle situatedrelatively close to the skin surface of the central and left anteriorchest. These factors, together with larger size and more powerfulimpulse generation from the ventricles, contribute to the relativelylarger amplitudes of ventricular waveforms.

Nevertheless, as explained supra, both the P-wave and the R-wave arerequired for the physician to make a proper rhythm diagnosis from thedozens of arrhythmias that can occur. Yet, the quality of P-waves ismore susceptible to weakening from distance and the intervening tissuesand structures and from signal attenuation and signal processing thanthe high voltage waveforms associated with ventricular activation. Theadded value of avoiding further signal attenuation resulting from dermalimpedance makes a subcutaneous P-wave centric ICM even more likely tomatch, or even outperform dermal ambulatory monitors designed toanalogous engineering considerations and using similar sensing circuitryand components, compression algorithms, and physical layout ofelectrodes, such as described in U.S. Pat. No. 9,545,204, issued Jan.17, 2017 to Bishay et al.; U.S. Pat. No. 9,730,593, issued Aug. 15, 2017to Felix et al.; U.S. Pat. No. 9,700,227, issued Jul. 11, 2017 to Bishayet al.; U.S. Pat. No. 9,717,433, issued Aug. 1, 2017 to Felix et al.;and U.S. Pat. No. 9,615,763, issued Apr. 11, 2017 to Felix et al., thedisclosures of which are incorporated by reference.

The ICM 212 can be implanted in the patient's chest using, for instance,a minimally invasive subcutaneous implantation instrument or othersuitable surgical implement. The ICM 212 is positioned slightly to theright or left of midline, covering the center third of the chest,roughly between the second and sixth ribs, approximately spanningbetween the level of the manubrium 8 and the level of the xiphoidprocess 9 on the inferior border of the sternum 203, depending upon thevertical build of the patient 210.

During monitoring, the amplitude and strength of action potentialssensed by an ECG devices, including dermal ECG monitors and ICMs, can beaffected to varying degrees by cardiac, cellular, extracellular, vectorof current flow, and physical factors, like obesity, dermatitis, lungdisease, large breasts, and high impedance skin, as can occur indark-skinned individuals. Performing ECG sensing subcutaneously in theparasternal region 211 significantly improves the ability of the ICM 212to counter some of the effects of these factors, particularly high skinimpedance and impedance from subcutaneous fat. Thus, the ICM 212exhibits superior performance when compared to conventional dermal ECGmonitors to existing implantable loop recorders, ICMs, and other formsof implantable monitoring devices by virtue of its engineering andproven P-wave documentation above the skin, as discussed in W. M. Smithet al., “Comparison of diagnostic value using a small, single channel,P-wave centric sternal ECG monitoring patch with a standard 3-leadHolter system over 24 hours,” Am. Heart J., March 20217; 2185:67-73, thedisclosure of which is incorporated by reference.

Moreover, the sternal midline implantation location in the parasternalregion 211 allows the ICM's electrodes to record an ECG of optimalsignal quality from a location immediately above the strongestsignal-generating aspects of the atrial. Signal quality is improvedfurther in part because cardiac action potential propagation travelssimultaneously along a north-to-south and right-to-left vector,beginning high in the right atrium and ultimately ending in theposterior and lateral region of the left ventricle. Cardiacdepolarization originates high in the right atrium in the SA node beforeconcurrently spreading leftward towards the left atrium and inferiorlytowards the atrioventricular (AV) node. On the proximal end 213, the ECGelectrodes of the ICM 212 are subcutaneously positioned with the upperor superior pole (ECG electrode) slightly to the right or left of thesternal midline in the region of the manubrium 8 and, on the distal end214, the lower or inferior pole (ECG electrode) is similarly situatedslightly to the right or left of the sternal midline in the region ofthe xiphoid process 9 and lower sternum 203. The ECG electrodes of theICM 212 are placed primarily in a north-to-south orientation along thesternum 203 that corresponds to the north-to-south waveform vectorexhibited during atrial activation. This orientation corresponds to theaVF lead used in a conventional 12-lead ECG that is used to sensepositive or upright P-waves. In addition, the electrode spacing and theelectrodes' shapes and surface areas mimic the electrodes used in theICM's dermal cousin, designed as part of the optimal P-wave sensingelectrode configuration, such as provided with the dermal ambulatorymonitors cited supra.

Despite the challenges faced in capturing low amplitude cardiac actionpotentials, the ICM 212 is able to operate effectively using only twoelectrodes that are strategically sized and placed in locations ideallysuited to high fidelity P-wave signal acquisition. This approach hasbeen shown to clinically outperform more typical multi-lead monitorsbecause of the improved P-wave clarity, as discussed in W. M. Smith etal., cited supra. FIGS. 13 and 14 are respectively top and bottomperspective views showing the ICM 212 of FIG. 1. Physically, the ICM 212is constructed with a hermetically sealed implantable housing 215 withat least one ECG electrode forming a superior pole on the proximal end213 and at least one ECG electrode forming an inferior pole on thedistal end 214.

When implanted, the housing 215 is oriented most cephalad. The housing215 is constructed of titanium, stainless steel or other biocompatiblematerial. The housing 215 contains the sensing, recordation andinterfacing circuitry of the ICM 212, plus a long life battery. Awireless antenna is integrated into or within the housing 215 and can bepositioned to wrap around the housing's internal periphery or locationsuited to signal reception. Other wireless antenna placement orintegrations are possible.

Physically, the ICM 212 has four ECG electrodes 216, 217, 218, 219.There could also be additional ECG electrodes, as discussed infra. TheECG electrodes include two ventral (or dorsal) ECG electrodes 218, 219and two wraparound ECG electrodes 216, 217. One ventral ECG electrode218 is formed on the proximal end 213 and one ventral ECG electrode 219is formed on the distal end 214. One wraparound ECG electrode 216 isformed circumferentially about the proximal end 213 and one wraparoundECG electrode 217 is formed circumferentially about the distal end 214.Each wraparound ECG electrode 216, 217 is electrically insulated fromits respective ventral ECG electrode 218, 219 by a periphery 220, 221.

The four ECG electrodes 216, 217, 218, 219 are programmaticallycontrolled by a microcontroller through onboard firmware programming toenable a physician to choose from several different electrodeconfigurations that vary the electrode surface areas, shapes, andinter-electrode spacing. The sensing circuitry can be programmed, eitherpre-implant or in situ, to use different combinations of the availableECG electrodes (and thereby changing electrode surface areas, shapes,and inter-electrode spacing), including pairing the two ventral ECGelectrodes 216, 217, the two wraparound ECG electrodes 218, 219, or oneventral ECG electrode 216, 217 with one wraparound ECG electrode 218,219 located on the opposite end of the housing 215. In addition, theperiphery 220, 221 can be programmatically controlled to logicallycombine the wraparound ECG electrode 216, 217 on one end of the ICM 212with its corresponding ventral ECG electrode 218, 219 to form a singlevirtual ECG electrode with larger surface area and shape. (Althoughelectronically possible, the two ECG electrodes that are only on one endof the ICM 212, for instance, wraparound ECG electrode 216 and ventralECG electrode 218, could be paired; however, the minimal inter-electrodespacing would likely yield a signal of poor fidelity in mostsituations.)

In a further embodiment, the housing 215 and contained circuitry can beprovided as a standalone ICM core assembly to which a pair of compatibleECG electrodes can be operatively coupled to form a full implantable ICMdevice.

Other ECG electrode configurations are possible. For instance,additional ECG electrodes can be provided to increase the number ofpossible electrode configurations, all of which are to ensure betterP-wave resolution. FIG. 15 is a bottom perspective view showing the ICM212 of FIG. 12 in accordance with a further embodiment. An additionalpair of ventral ECG electrodes 222, 223 are included on the housing'sventral surface. These ventral ECG electrodes 222, 223 are spaced closertogether than the ventral ECG electrodes 218, 219 on the ends of thehousing 215 and a physician can thus choose to pair the two innerventral ECG electrodes 222, 223 by themselves to allow for minimalelectrode-to-electrode spacing, or with the other ECG electrodes 216,217, 218, 219 to vary electrode surface areas, shapes, andinter-electrode spacing even further to explore optimal configurationsto acquire the P-wave.

Other housing configurations of the ICM are possible. For instance, thehousing of the ICM can be structured to enhance long term comfort andfitment, and to accommodate a larger long life battery or more circuitryor features, including physiologic sensors, to provide additionalfunctionality. FIGS. 16 and 17 are respectively top and bottomperspective views showing an ICM 230 in accordance with a still furtherembodiment. The ICM 230 has a housing 231 with a tapered extension 232that is terminated on the distal end with an electrode 234. On aproximal end, the housing 231 includes a pair of ECG electrodeselectrically insulated by a periphery 237 that include a ventral ECGelectrode 233 and a wraparound ECG electrode 234. In addition, a ventralECG electrode 236 is oriented on the housing's distal end before thetapered extension 232. Still other housing structures and electrodeconfigurations are possible.

In general, the basic electrode layout is sufficient to sense cardiacaction potentials in a wide range of patients. Differences in thoracictissue density and skeletal structure from patient to patient, though,can affect the ability of the sensing electrodes to efficaciouslycapture action potential signals, yet the degree to which signalacquisition is affected may not be apparent until after an ICM has beenimplanted and deployed, when the impacts of the patient's physicalconstitution and his patterns of mobility and physical movement on ICMmonitoring can be fully assessed.

In further embodiments, the electrodes can be configured post-implant toallow the ICM to better adapt to a particular patient's physiology. Forinstance, electrode configurations having more than two sensingelectrodes are possible. FIG. 18 is a plan view showing furtherelectrode configurations. Referring first to FIG. 18(a), a single discECG electrode 240 could be bifurcated to form a pair of half-circle ECGelectrodes 241, 242 that could be programmatically selected or combinedto accommodate a particular patients ECG signal characteristics post-ICMimplant. Referring next to FIG. 18(b), a single disc ECG electrode 245could be divided into three sections, a pair of crescent-shaped ECGelectrodes 246, 247 surrounding a central semicircular ECG electrode 248that could similarly be programmatically selected or combined. Stillother ECG electrode configurations are possible.

ECG monitoring and other functions performed by the ICM 212 are providedthrough a micro controlled architecture. FIG. 19 is a functional blockdiagram showing the P-wave focused component architecture of thecircuitry 280 of the ICM 212 of FIG. 12. The circuitry 280 is poweredthrough the long life battery 21 provided in the housing 215, which canbe a direct current battery. Operation of the circuitry 280 of the ICM212 is managed by a microcontroller 281, such as the EFM32 Tiny Gecko32-bit microcontroller, manufactured by Silicon Laboratories Inc.,Austin, Tex. The microcontroller 281 has flexible energy managementmodes and includes a direct memory access controller and built-inanalog-to-digital and digital-to-analog converters (ADC and DAC,respectively). The microcontroller 281 also includes a program memoryunit containing internal flash memory (not shown) that is readable,writeable, and externally programmable.

The microcontroller 281 operates under modular micro program control asspecified in firmware stored in the internal flash memory. Themicrocontroller 281 draws power from the battery provided in the housing215 and connects to the ECG front end circuit 63. The front end circuit63 measures raw subcutaneous electrical signals using a driven referencesignal that eliminates common mode noise, as further described infra.

The circuitry 280 of the ICM 212 also includes a flash memory 282external to the microcontroller 281, which the microcontroller 281 usesfor continuously storing samples of ECG monitoring signal data and otherphysiology, such as respiratory rate, blood oxygen saturation level(SpO₂), blood pressure, temperature sensor, and physical activity, anddevice and related information. The flash memory 282 also draws powerfrom the battery provided in the housing 215. Data is stored in a serialflash memory circuit, which supports read, erase and program operationsover a communications bus. The flash memory 282 enables themicrocontroller 281 to store digitized ECG data. The communications busfurther enables the flash memory 282 to be directly accessed wirelesslythrough a transceiver 285 coupled to an antenna 217 built into (orprovided with) the housing 215. The transceiver 285 can be used forwirelessly interfacing over Bluetooth or other types of wirelesstechnologies for exchanging data over a short distance with a pairedmobile device, including smartphones and smart watches, that aredesigned to communicate over a public communications infrastructure,such as a cellular communications network, and, in a further embodiment,other wearable (or implantable) physiology monitors, such as activitytrackers worn on the wrist or body. Other types of device pairings arepossible, including with a desktop computer or purpose-built bedsidemonitor. The transceiver 285 can be used to offload stored ECGmonitoring data and other physiology data and information and for devicefirmware reprogramming. In a further embodiment, the flash memory 282can be accessed through an inductive coupling (not shown).

The microcontroller 281 includes functionality that enables theacquisition of samples of analog ECG signals, which are converted into adigital representation, implementing the method 100 described supra withreference to FIG. 10. In one mode, the microcontroller 281 implements aloop recorder feature that will acquire, sample, digitize, signalprocess, and store digitized ECG data into available storage locationsin the flash memory 282 until all memory storage locations are filled,after which existing stored digitized ECG data will either beoverwritten through a sliding window protocol, albeit at the cost ofpotentially losing the stored data that was overwritten, if notpreviously downloaded, or transmitted wirelessly to an external receiverto unburden the flash memory. In another mode, the stored digitized ECGdata can be maintained permanently until downloaded or erased to restorememory capacity. Data download or erasure can also occur before allstorage locations are filled, which would free up memory space sooner,albeit at the cost of possibly interrupting monitoring while downloadingor erasure is performed. Still other modes of data storage and capacityrecovery are possible.

The circuitry 280 of the ICM 212 can include functionality toprogrammatically select pairings of sensing electrodes when the ICM 212is furnished with three or more electrodes. In a further embodiment,multiple sensing electrodes could be provided on the ICM 212 to providea physician the option of fine-tuning the sensing dipole (or tripole ormultipole) in situ by parking active electrodes and designating anyremaining electrodes inert. The pairing selection can be made remotelythrough an inductive coupling or by the transceiver 285 via, forinstance, a paired mobile device, as further described infra. Thus, thesensing electrode configuration, including number of electrodes,electrode-to-electrode spacing, and electrode size, shape, surface area,and placement, can be modified at any time during the implantation ofthe ICM 212.

In a further embodiment, the circuitry 280 of the ICM 212 can include anactigraphy sensor 284 implemented as a 3-axis accelerometer. Theaccelerometer may be configured to generate interrupt signals to themicrocontroller 281 by independent initial wake up and free fall events,as well as by device position. In addition, the actigraphy provided bythe accelerometer can be used during post-monitoring analysis to correctthe orientation of the ICM 212 if, for instance, the ICM 212 has beeninadvertently implanted upside down, that is, with the ICM's housingoriented caudally, as well as for other event occurrence analyses. In astill further embodiment, the circuitry 280 of the ICM 212 can includeone or more physiology sensors. For instance, a physiology sensor can beprovided as part of the circuitry 280 of the ICM 212, or can be providedon the electrode assembly 214 with communication with themicrocontroller 281 provided through a circuit trace. The physiologysensor can include an SpO₂ sensor, blood pressure sensor, temperaturesensor, respiratory rate sensor, glucose sensor, airflow sensor,volumetric pressure sensing, or other types of sensor or telemetricinput sources.

In a yet further embodiment, firmware with programming instructions,including machine learning and other forms of artificialintelligence-originated instructions, can be downloaded into themicrocontroller's internal flash memory. The firmware can includeheuristics to signal patient and physician with alerts over healthconditions or arrhythmias of selected medical concern, such as where aheart pattern particular to the patient is identified and the ICM 212 isthereby reprogrammed to watch for a reoccurrence of that pattern, afterwhich an alert will be generated and sent to the physician (or othercaregiver) through the transceiver 285 via, for instance, a pairedmobile device. Similarly, the firmware can include heuristics that canbe downloaded to the ICM 212 to actively identify or narrow down apattern (or even the underlying cause) of sporadic cardiac conditions,for instance, atrial tachycardia (AT), atrial fibrillation (AF), atrialflutter (AFL), AV node reciprocating tachycardia, ventriculartachycardia (VT), sinus bradycardia, asystole, complete heart block, andother cardiac arrhythmias, again, after which an alert will be generatedand sent to the physician (or other caregiver) through the transceiver285. For instance, an alert that includes a compressed ECG digitizedsample can also be wirelessly transmitted by the ICM 212 upon thetriggering of a preset condition, such as an abnormally low heart ratein excess of 170 beats per minute (bpm), an abnormally low heart ratefalling below 30 bpm, or AF detected by onboard analysis of RR intervalvariability by the microcontroller 281. Finally, a similar methodologyof creating firmware programming tailored to the monitoring and medicaldiagnostic needs of a specific patient (or patient group or generalpopulation) can be used for other conditions or symptoms, such assyncope, palpitations, dizziness and giddiness, unspecified convulsions,abnormal ECG, transient cerebral ischemic attacks and related syndromes,cerebral infarction, occlusion and stenosis of pre-cerebral and cerebralarteries not resulting in cerebral infarction personal history oftransient ischemic attack, and cerebral infarction without residualdeficits, to trigger an alert and involve the physician or initiateautomated analysis and follow up back at the patient's clinic. Finally,in a still further embodiment, the circuitry 280 of the ICM 212 canaccommodate patient-interfaceable components, including an externaltactile feedback device (not shown) that wirelessly interfaces to theICM 212 through the transceiver 285. A patient 210 can press theexternal tactile feedback device to mark events, such as a syncopeepisode, or to perform other functions. The circuitry 280 can alsoaccommodate triggering an external buzzer 67, such as a speaker,magnetic resonator or piezoelectric buzzer, implemented as part of theexternal tactile feedback device or as a separatewirelessly-interfaceable component. The buzzer 67 can be used by themicrocontroller 281 to indirectly output feedback to a patient 210, suchas a low battery or other error condition or warning. Still othercomponents, provided as either part of the circuitry 280 of the ICM 212or as external wirelessly-interfaceable devices, are possible.

The ECG front end circuit 283 of the ICM 12 measures raw subcutaneouselectrical signals using a driven reference signal, such as described inU.S. Pat. Nos. 9,700,227, 9,717,433, and 9,615,763, cited supra. Thedriven reference signal effectively reduces common mode noise, powersupply noise and system noise, which is critical to preserving thecharacteristics of low amplitude cardiac action potentials, especiallythe P wave signals originating from the atria. The ECG front end circuit283 is organized into a passive input filter stage, a unity gain voltagefollower stage, a passive high pass filtering stage, a voltageamplification and active filtering stage, and an anti-aliasing passivefilter stage, plus a reference generator. The passive input filter stagepassively shifts the frequency response poles downward to counter thehigh electrode impedance from the patient on the signal lead andreference lead, which reduces high frequency noise. The unity gainvoltage follower stage allows the circuit to accommodate a very highinput impedance, so as not to disrupt the subcutaneous potentials or thefiltering effect of the previous stage. The passive high pass filteringstage includes a high pass filter that removes baseline wander and anyoffset generated from the previous stage. As necessary, the voltageamplification and active filtering stage amplifies or de-amplifies (orallows to pass-through) the voltage of the input signal, while applyinga low pass filter. The anti-aliasing passive filter stage provides ananti-aliasing low pass filter. The reference generator drives a drivenreference signal containing power supply noise and system noise to thereference lead and is connected directly to the patient, therebyavoiding the thermal noise of the protection resistor that is includedas part of the protection circuit.

Once collected, the ECG data is offloaded from the cardiac monitor to adatabase, computer, or mobile device via a wired or wireless connection.The ECG data can be stored or collected in real time, and can betransferred through a physical connection, a short-range wirelessconnection, or a network-based connection. FIG. 20 is a functional blockdiagram showing a system 300 for obtaining ECG data from a cardiacmonitor, in accordance with one embodiment. The cardiac monitor 301 canbe dermally positioned on a patient or can be implanted for monitoringECG data, which can be offloaded for storage and further processing.

Physical Download Station

In one embodiment, when dermally positioned, the cardiac monitor 301 canbe connected to a download station 302, which could be a programmer orother device that permits the retrieval of stored ECG monitoring data,execution of diagnostics on or programming of the monitor 301, orperformance of other functions, via a receptacle 303. In turn, thedownload station 125 executes a communications or offload program 304(“Offload”) or similar program that interacts with the cardiac monitor301 via the physical interface to retrieve the stored ECG monitoringdata. The download station 302 could be a server, personal computer,tablet or handheld computer, smart mobile device, or purpose-builtprogrammer designed specific to the task of interfacing with a monitorrecorder 14. Still other forms of download stations 302 are possible.Generally, the download station is located in a physician's office, inwhich the patient must be present. Alternatively, the patient can sendin the dermal device for offloading the ECG data. Whether the patient islocated in the office or sends in the device, real-time ECG data cannotbe accessed since the cardiac monitor is removed from the patient.

Upon retrieving stored ECG monitoring data from the cardiac monitor 301,middleware first operates on the retrieved data to adjust the ECGcapture quality, as necessary, and to convert the retrieved data into aformat suitable for use by third party post-monitoring analysissoftware. The formatted data can then be retrieved from the downloadstation 302 over a hard link 313 using a control program 314 (“Ctl”) oranalogous application executing on a personal computer 315 or otherconnectable computing device, via a communications link (not shown),whether wired or wireless, or by physical transfer of storage media (notshown). The personal computer 315 or other connectable device may alsoexecute middleware that converts ECG data and other information into aformat suitable for use by a third-party post-monitoring analysisprogram. In a further embodiment, the download station 302 is able todirectly interface with other devices over a computer communicationsnetwork 312, which could be some combination of a local area network anda wide area network, including the Internet, over a wired or wirelessconnection.

A client-server model could be used to employ a server 308 to remotelyinterface with the download station 302 over the network 312 andretrieve the formatted data or other information. The server 308executes a patient management program 316 (“Mgt”) or similar applicationthat stores the retrieved formatted data and other information in asecure database 309 cataloged in that patient's EMRs 310. The patientmanagement program 316, or other trusted application, also maintains andsafeguards the secure database 309 to limit access to patient EMRs 310to only authorized parties for appropriate medical or other uses, suchas mandated by state or federal law, such as under the Health InsurancePortability and Accountability Act (HIPAA) or per the European Union'sData Protection Directive.

Short-Range Wireless Connection

In a further embodiment, the cardiac monitor 301, whether dermallypositioned or implanted, can interoperate wirelessly with other wearablephysiology and activity sensors 305 and with wearable or mobilecommunications devices 306. Further, the cardiac monitor can function asa physiological monitor to measure not only ECG data, but other types ofphysiological measures, such as oxygen levels and blood glucose levels.Other types of physiological monitors and measures are possible.Wearable physiology and activity sensors 305 encompass a wide range ofwirelessly interconnectable devices that measure or monitor dataphysical to the patient's body, such as heart rate, temperature, bloodpressure, and so forth; physical states, such as movement, sleep,footsteps, and the like; and performance, including calories burned orestimated blood glucose level. These devices originate both within themedical community to sense and record traditional medical physiologythat could be useful to a physician in arriving at a patient diagnosisor clinical trajectory, as well as from outside the medical community,from, for instance, sports or lifestyle product companies who seek toeducate and assist individuals with self-quantifying interests.

Each of the wearable physiology and activity sensors and the wearable ormobile communications devices can communicate via a short-range wirelessconnection, such as Bluetooth, with the cardiac monitor. However, due tothe short-range connection, the patient must be proximate to the sensorsand the communications devices.

The wearable physiology and activity sensor 305 and the wearable ormobile communications devices 306 could also serve as a conduit forproviding the data collected by the wearable physiology and activitysensor 305 to a server 308. The server 308 could then merge thecollected data into the wearer's electronic medical records, EMRs, 310in the secure database 309, if appropriate (and permissible), or theserver 308 could perform an analysis of the collected data, perhapsbased by comparison to a population of like wearers of the wearablephysiology and activity sensor 305. Further, the ECG data can beprovided to a remotely located physician or other medical professionalfor review. However, even though the ECG data may be transferred in realtime from the cardiac monitor to the wearable physiology and activitysensor 305 or the wearable or mobile communications devices 306 viaBluetooth, the ECG data is delayed to the remote physician due to theauthentication required when the data is transferred over the network tothe server.

Alternatively, the wearable physiology and activity sensors 305 arecapable of wireless interfacing with wearable or mobile communicationsdevices 306, particularly smart mobile devices, including so-called“smart phones,” to download monitoring data either in real-time or inbatches. The wearable or mobile communications device 306 executes anapplication (“App”) 307 that can retrieve the data collected by thewearable physiology and activity sensor 305 and evaluate the data togenerate information of interest to the wearer, such as an estimation ofthe effectiveness of the wearer's exercise efforts. Still other wearableor mobile communications device 306 functions on the collected data arepossible.

In a further embodiment, a wireless data transfer device can be placedover the patient's chest at a location of the cardiac monitor 301 andthe ECG data can be transferred to a computer or mobile device via thewireless data transfer device. In one embodiment, such transfer of datacan occur via Bluetooth since the patient must be located in thephysician's office or medical facility. The ECG data can subsequently betransferred from the data transfer device to a server via a network. Asdescribed above, transfer of the ECG data over the network to a webserver is delayed due to the authentication process.

Network-Based Communication

In addition, the cardiac monitor 301 could wirelessly interface directlywith the server 308, personal computer 311, or other computing deviceconnectable over the network 312, when the cardiac monitor 301 isappropriately equipped for interfacing with such devices. However, adelay of the data is created and a remote medical professional is unableto access the ECG data in real time. Specifically, in internet-basedconnections, such as between the puck or cardiac monitor to the webserver, the transfer of ECG data is too slow to provide real-time ornear real-time streaming of the data to a remote viewer, such as amedical professional. Generally, for real-time or near real-time viewingof ECG data a one second delay or shorter is required. When the ECG datais first transferred to a web server via a network, a secure connectionmust be established, such as via the TLS Handshake Protocol that isresponsible for authenticating new secure sessions and resuming previoussecure sessions. Although secure, such connection requires time toestablish, which delays the ECG data being accessed and provided to thephysician or medical professional.

To reduce the amount of time establishing a connection for the transferof ECG data, a continuous data connection can be established. FIG. 21 isa functional block diagram showing a system 320 for real-time remotestreaming of ECG data, in accordance with one embodiment. A cardiacmonitor 322 is dermally positioned or implanted in a patient 321 tocapture cardiac action potentials sensed by ECG sensing electrodes whichare output as ECG signals. The cardiac monitor 322 can include, at aminimum, a pair of electrodes, a battery, processor, front end, memory,and a wireless transceiver. In one embodiment, the wireless transceivercan include a Near-field communication (NFC) chip that controls theexchange of data between the cardiac monitor 322 and external devices ata short-range, though other communication protocols can also be used bythe transceiver at a short range. The presence of NFC or othercommunication protocols allows the wireless transceiver to implement acryptographic security protocol with an external device, protecting databeing exchanged.

In one embodiment, the ECG data can be offloaded directly from thecardiac monitor 322 via a wireless connection, over an internetwork 325,such as the Internet, to a server 326 in the cloud. Specifically, theECG data is first encrypted by the cardiac monitor, such as via the NFCchip, and a continuous connection is established with the cloud server326. The cloud server 326 then transfers the ECG data in real time to aphysician or other medical professional 328 via a computing device, suchas a computer, tablet, or cellular phone 327.

In a further embodiment, a data transfer device, such as a puck 324, canbe used to obtain data from the cardiac monitor 322. The puck 324 can beshaped as a circle, oval, or computer mouse, and can be pressed against(or held close to) the patient's chest in the parasternal region overthe cardiac monitor 322 to access ECG data and provide charging to thecardiac monitor 322. Other shapes of the puck 324 are possible. At aminimum, the puck should include a housing, processor, battery, memory,and a wireless transceiver or NFC chip. The puck 322 can access the ECGdata from the cardiac monitor 322 via the wireless transceiver or an NFCchip. If the ECG data is not already encrypted, the puck 324 can encryptthe ECG data. Once obtained, the puck 324 can transmit the encrypted ECGdata to the cloud server 326 or to a home station 323.

Specifically, the puck 324 can include a data download module (notshown), which uses an internal wireless transceiver to wirelesslydownload data collected by the cardiac monitor 322 by interfacing withthe wireless transceiver cardiac monitor. The downloading of the ECGdata can happen simultaneously to charging of the cardiac monitor by thepuck, as described below. The downloaded physiological data can in turnbe wirelessly forwarded to a home station or the cloud server.

The home station 323 can be located at the patient's home, such as nearthe patient's bed, and can include a housing, processor, inductivebattery charger, control circuit, memory, and wireless transceiver orNFC chip. The home station 323 can be used to communicate data to andfrom the cardiac monitor 322, program the cardiac monitor, and chargethe puck 324. The data can include ECG data, as well as other types ofphysiological data, obtained by the cardiac monitor, such as respiratorrate, blood glucose levels, and oxygen levels, and can be collected atleast once a day or over longer periods of time. In a furtherembodiment, the cardiac monitor 322 can communicate the ECG data andphysiological data directly to the home station 323, without the use ofthe puck 324.

Cardiac or other types of physiological monitors, whether dermallyplaced on a patient or implanted, are not usually responsible forcreating or initiating a secure communication channel, but can do so byincluding a secret key in the cardiac monitor. The secret key would onlybe known by the cloud server and all the data, including ECG and otherphysiological data, transferred between the cardiac monitor and cloudserver would be encrypted with the key, even if the data first goesthrough a puck or home station. The cardiac and physiological monitorscan be positioned dermally on a patient or implanted, such as thosedevices described in detail in U.S. Provisional Patent Application No.62/874,086, filed Jul. 15, 2019; U.S. Provisional Patent Application No.62/873,740, filed Jul. 12, 2019; and U.S. Provisional Patent ApplicationNo. 62/962,773, filed Jan. 17, 2020, the disclosures of which areincorporated by reference and cover a configurable hardware platform forhealth and medical monitoring of physiology that is housed within ahermetically sealed implantable medical device (IMD). In one embodiment,the IMD is equipped with one or more physiological sensors thatnon-exhaustively include ECG, temperature, oxygen saturation,respiration, and blood glucose. Physically, the IMD has a generallytubular shape that includes a central tubular body with rounded semispherical ends. When configured to measure electrocardiographic signals,the central tubular body and one of the semi spherical ends function aselectrode dipoles. That semi spherical end is electrically conductiveyet electrically insulated from the central tubular body. As well, theoutside surface of the central tubular body is partially electricallyinsulated, generally on the surface closest to the electricallyconductive semi spherical end to form a non-electrically conductiveinversion with only the outside surface distal to that semi sphericalend being exposed. When placed within the central tubular body, afoldable printed circuit board (PCB) forms three aspects thatrespectively define a low frequency antenna for energy flux capture, ahigh frequency antenna for radio frequency (RF) data exchange, and acentral tri-folded aspect containing a microcontroller and devicecircuitry. A power source that includes a rechargeable battery is alsoplaced within the 1 MB to one end of the folded PCB and in electricalcontact through a protection circuit with the electrically conductivesemi spherical end, thereby serving as an electrical feedthrough to thePCB. The battery may be recharged using a non-contact method, such asinductive charging, resonant charging, energy harvesting, thermalgradient charging, ultrasonic charging, RF-based charging or charging byambient or driven motion. Different types of recharging processes can beused as described in U.S. patent application Ser. No. 16/919,626, filedon Jul. 2, 2020, the disclosure of which is incorporated by reference.

The encrypted ECG data received on the home station 323, from the puckor the cardiac monitor, can be delivered via WiFi or a cellularconnection to the cloud server 326 and subsequently, to the physician328 via a computer, tablet, or cellular phone 327, without compromisingdata security due to the encryption of the data. The home station 323maintains a continuous connection with the cloud server 326, which doesnot require authentication of the home station every time, includingstartup and a handshake protocol, which reduces an amount of time for aremote user, such as the physician, to receive the ECG data. Further,the home station 323 includes an inductive charger to charge the puckwhen not in use.

When applied to a patient, the charged puck 324 can charge the cardiacmonitor 322. For instance, the puck can include an energy transmissionmodule (not shown) to provide input, such as magnetic or radio waves,that provides electrical energy to the cardiac monitor 322 duringcharging. For example, the energy transmission module can include aradio transmitter that radiates radio waves that can be captured by thecardiac monitor 322, such as via an antenna. Alternatively, the ECG datacan be transmitted via an inductive coil (not shown) included in thepuck to generate a magnetic field that energizes an inductive coilwithin the cardiac monitor 322. Charging of the cardiac monitor duringdata transfer is useful to prevent draining the battery during thetransfer and to further power the battery for later use.

ECG streaming is useful for adjusting beat detection and noise detectionparameters of the cardiac monitor to ensure that the ECG data isaccurate. Currently, beat detection and noise detection adjustments aremade while the patient is present at the physician's office since theadjustments are generally based on real time ECG views. Otherparameters, such as arrhythmia detection, can also occur. However, suchparameters can be adjusted remotely using the remote real-time ECGstreaming. In one example, beat detection can use the amplitude andchange in volts per second to identify heart beats of the patient.Certain patterns can fool a beat detector and change the points in anR-R plot. Accordingly, accurately identifying beats is important.

In one embodiment, beat detection can occur on the cardiac monitor.Alternatively or in addition to the monitor, beat detection can occur ona server. The beat detection algorithm for the patient can be improvedby comparing the beat detection results from the monitor with the beatdetection results from the server. For example, the comparison can occuron the server, which can also do the tuning of the beat detection of thecardiac monitor. The updated beat parameters are then sent to thecardiac monitor. Such comparison can occur daily, such as part of adaily interrogation of data from the cardiac monitor.

In one example, beat detection may need to be adjusted for a patient.For instance, when a patient first receives an ICM, a fibrous capsulehas not yet formed and the tissue is bleeding and swollen. As thepatient recovers, the patient's cardiac signals usually grow and thebeat detection algorithm should be adjusted.

In a further embodiment, direct transfer of ECG data from the cardiacmonitor to the home station can also be useful in doctors' offices. Forexample, patients with cardiac devices are sitting in a waiting room atthe physician's office. While waiting, the cardiac devices can encryptthe ECG or other physiological data, and send the encrypted data to ahome station located at the physician's office so that the data isreadily available when the patient is called to see the doctor. Sincethe data is encrypted by the cardiac monitor, the data is secure despitethe multiple monitors that are offloading data simultaneously. Further,the encrypted data can only be unencrypted in the cloud.

Although the above has discussed real-time streaming of cardiac data,other types of physiological data can be streamed, oxygen rate,temperature, respiratory rate, blood glucose levels, and more. Themonitors for the physiological data can be included on the cardiacmonitor or can be separate from the cardiac monitor.

While the invention has been particularly shown and described asreferenced to the embodiments thereof, those skilled in the art willunderstand that the foregoing and other changes in form and detail maybe made therein without departing from the spirit and scope.

What is claimed is:
 1. A system for remote ECG data streaming inreal-time, comprising: a physiological monitor affixed to a chest of apatient or implanted within the patient to establish a continuousconnection with a cloud-based server and comprising at least twoelectrodes and a wireless transceiver to transmit encrypted ECG datacollected via one or more electrodes, where in the encrypted ECG data isencrypted via a secret key stored on the physiological monitor; and acomputing device associated with at least one user to receive theencrypted ECG data transmitted from the cloud-based server in real-time.2. A system according to claim 1, wherein the secret key is known to thecloud-based server.
 3. A system according to claim 1, wherein thephysiological monitor performs beat detection using the ECG data.
 4. Asystem according to claim 1, wherein the cloud-based server performsbeat detection using the ECG data.
 5. A system according to claim 1,wherein each of the physiological monitor and cloud-based server performbeat detection using the ECG data and the cloud-based server comparesresults of the beat detection from the physiological monitor withresults of the beat detection from the cloud-based server.
 6. A systemaccording to claim 5, wherein the comparison of the beat detectionresults is performed on a predetermined basis.
 7. A system according toclaim 1, wherein the physiological monitor comprises one or more of anSp0₂ sensor, blood pressure sensor, temperature sensor, respiratory ratesensor, glucose sensor, airflow sensor, and volumetric pressure sensor.8. A system according to claim 1, further comprising: one or morephysiology and activity sensors separate from the physiological monitorthat each interoperate wirelessly with the physiological monitor.
 9. Asystem according to claim 8, wherein the physiological monitor and oneor more physiology and activity sensors communicate via Bluetooth.
 10. Asystem according to claim 8, wherein the physiological monitor encryptsdata obtained via the one or more physiology and activity sensors.
 11. Amethod for remote ECG data streaming in real-time, comprising:establishing a continuous connection between a cloud-based server and aphysiological monitor comprising at least two electrodes and affixed toa chest of a patient or implanted within the patient; collecting ECGdata via one or more of the electrodes; encrypting via a wirelessinterface on the physiological monitor the ECG data, wherein the ECGdata is encrypted via a secret key stored on the physiological monitor;and receiving on a computing device associated with at least one user inreal-time the encrypted ECG data transmitted from the cloud-basedserver.
 12. A method according to claim 11, wherein the secret key isknown to the cloud-based server.
 13. A method according to claim 11,wherein the physiological monitor performs beat detection using the ECGdata.
 14. A method according to claim 11, wherein the cloud-based serverperforms beat detection using the ECG data.
 15. A method according toclaim 11, wherein each of the physiological monitor and cloud-basedserver perform beat detection using the ECG data and the cloud-basedserver compares results of the beat detection from the physiologicalmonitor with results of the beat detection from the cloud-based server.16. A method according to claim 15, wherein the comparison of the beatdetection results is performed on a predetermined basis.
 17. A methodaccording to claim 11, wherein the physiological monitor comprises oneor more of an Sp0₂ sensor, blood pressure sensor, temperature sensor,respiratory rate sensor, glucose sensor, airflow sensor, and volumetricpressure sensor.
 18. A method according to claim 11, further comprising:one or more physiology and activity sensors separate from thephysiological monitor that each interoperate wirelessly with thephysiological monitor.
 19. A method according to claim 18, wherein thephysiological monitor and one or more physiology and activity sensorscommunicate via Bluetooth.
 20. A method according to claim 18, whereinthe physiological monitor encrypts data obtained via the one or morephysiology and activity sensors.